The invention relates to an electromechanical wheel brake device set forth hereinafter.
A wheel brake device of this kind has been disclosed by DE 196 31 592 A1. The known wheel brake device has an electric motor which, in order to actuate the wheel brake device by way of a worm gear, i.e. an angular gear, drives a nut of a screw link actuator to rotate. A spindle of the screw link actuator presses a frictional brake lining against a brake body and thus produces a brake force or a brake moment. The known wheel brake device is embodied as a disk brake with a floating caliper; the electric motor, the worm gear, and the screw link actuator are accommodated in the floating caliper. The brake body is a brake disk that is connected in a rotationally fixed manner to a vehicle wheel. The screw link actuator is a rotation/translation conversion gear that converts a rotating drive motion of the angular gear into a translational motion for pressing the frictional brake lining against the brake body or releasing the brake lining from the brake body. In lieu of the nut, the spindle can be driven in a rotary fashion and the displacement motion of the nut thus produced can be used for the pressure application of the frictional brake lining.
The known wheel brake device with the worm gear has the disadvantage that depending on its type, the worm drive has a high proportion of sliding friction and as a result, has a poor efficiency and a high degree of wear. The wear reduces the efficiency over the service life. Moreover, there is a poor starting behavior as a result of the high degree of sliding friction, which impairs the ability of the wheel brake device to be metered. Due to the high proportion of sliding friction, which is required in principle, a large part of the energy is lost, primarily in reverse operation as an adjusting or -positioning gear. This results in a high degree of stress on the electric motor and its power supply.